One example of present tree processing units may be found described in Canadian Pat. No. 1,055,366 issued May 29, 1979 to Roger Sigouin. Such apparatus comprises a boom processing unit, supported on a vehicle, which enables extension and retraction of a longitudinal boom having, at one end, tree gripping and debranching elements adapted to grasp a felled tree and to remove the branches therefrom. Further tree gripping elements are mounted to the unit and are adapted to grasp the tree trunk adjacent its butt end; debranching is carried out by extending the boom as the first gripping elements loosely hold the tree. The present method of delimbing trees consists of stationing the vehicle adjacent to limbed trees piled along a road side, grasping the trees, delimbing over a limb covered area and piling trees over another area.
The actual productivity of such apparatus depends on various factors such as the number of trees which can be picked-up each time, the skill level of the operator, the tree size and length.